Title:
METHOD AND APPARATUS FOR BENDING HOLLOW DOUBLE TUBE
Document Type and Number:
Japanese Patent JP3943958
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a method and an apparatus capable of bending a hollow double pipe having a narrow space between inner and outer pipes and thin thickness for using an exhaust pipe of an internal combustion engine for automobile and the like.
SOLUTION: In the method of bending a hollow double pipe by inserting core metals into the inner pipe 11 of the hollow double pipe 10 and the space between the inner pipe 11 and the outer pipe 12 to preform bending work by a bending die 2, almost the entire inner pipe 10 except for one edge is formed to have a rough oval section and inserted into the outer pipe 12, the intermediate core metals 7a, 7b having lingual shapes are arranged between the inner and outer pipes, and at the same time, the inner core metal 6 having a forming core metal 62, which has a rough oval section at its tip, is inserted into the inner pipe and bent by the bending die. After that, the inner and outer pipes are relatively moved to the inner core metal and the diameter of the perimeter surface is extended in the short axis direction of the inner pipe having the rough oval section to form a concentric circle relative to the outer pipe.
Inventors:
Arai Saburo
Application Number:
JP2002049082A
Publication Date:
July 11, 2007
Filing Date:
February 26, 2002
Export Citation:
Assignee:
Sankei Giken Co., Ltd.
Vista Co., Ltd.
Vista Co., Ltd.
International Classes:
B21D9/00; F01N13/08; B21D7/025; B21D39/20; B21D53/84; F01N13/18; (IPC1-7): B21D9/00; B21D7/025; B21D39/20; F01N7/08; F01N7/18; //B21D53/84
Attorney, Agent or Firm:
Ryuji Takahashi
Shigeyuki Motoi
Shigeyuki Motoi
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